Lexra did implement a 32-bit variant of the [[Wikipedia:MIPS architecture|MIPS architecture]]. Noteworthy architectural feature was the lack of the [[Instruction_Set_Architecture#MIPS_I|MIPS I]] instructions <code>lwl, lwr, swl</code> and <code>swr</code> that optimize the handling of unaligned loads. Later the LX4580 core added hardware multithreading. Products implementing Lexra's architecture include the '''LX4080''', '''LX4080P''', '''LX4180''', '''LX4280''' and '''LX5280''', '''LX8000'''. Today Lexra is a defunct company. Several key employees of Lexra founded the digital video core company [http://www.ultradatacorp.com/ Ultra Data Corporation], the intellectual property assets of which have since been acquired. Many other key Lexra employees, including co-founder and CEO, Charlie Cheng, now work for ASIC vendor Faraday Technology in Taiwan, Sunnyvale, CA, and Framingham, MA. Lexra co-founder and CTO Pat Hays is now vice president of engineering for MIPS Technologies, Inc. in Mountain View.

+

Lexra did implement a 32-bit variant of the [[Wikipedia:MIPS architecture|MIPS architecture]]. Noteworthy architectural feature was the lack of the [[Instruction_Set_Architecture#MIPS_I|MIPS I]] instructions <code>lwl, lwr, swl</code> and <code>swr</code> that optimize the handling of [[Alignment|unaligned]] loads. Later the LX4580 core added hardware multithreading. Products implementing Lexra's architecture include the '''LX4080''', '''LX4080P''', '''LX4180''', '''LX4280''' and '''LX5280''', '''LX8000'''. Today Lexra is a defunct company. Several key employees of Lexra founded the digital video core company [http://www.ultradatacorp.com/ Ultra Data Corporation], the intellectual property assets of which have since been acquired. Many other key Lexra employees, including co-founder and CEO, Charlie Cheng, now work for ASIC vendor Faraday Technology in Taiwan, Sunnyvale, CA, and Framingham, MA. Lexra co-founder and CTO Pat Hays is now vice president of engineering for MIPS Technologies, Inc. in Mountain View.

Jonah Probell has written a [http://jonahprobell.com/lexra.html history of Lexra]

Jonah Probell has written a [http://jonahprobell.com/lexra.html history of Lexra]

Line 6:

Line 6:

The instructions <code>lwl, lwr, swl</code> and <code>swr</code> are covered by US&nbsp;patent 4,814,976. Lexra therefore choose to implement these instructions by software emulation. In the 1999&nbsp;- 2002 lawsuit of MIPS Technologies, Inc. vs. Lexra, Inc. about violation of this and a second patent, Lexra and MIPS reached an agreement and the court never ruled on the matter. Which means it isn't clear if Linux can or cannot legally emulate the instructions.

The instructions <code>lwl, lwr, swl</code> and <code>swr</code> are covered by US&nbsp;patent 4,814,976. Lexra therefore choose to implement these instructions by software emulation. In the 1999&nbsp;- 2002 lawsuit of MIPS Technologies, Inc. vs. Lexra, Inc. about violation of this and a second patent, Lexra and MIPS reached an agreement and the court never ruled on the matter. Which means it isn't clear if Linux can or cannot legally emulate the instructions.

Technically, support for Lexra processors without emulation of these instructions would be possible but it makes little sense since most software would rely in the instructions fairly heavily. A gcc patch that don't generate these instructions can be found on [http://gcc.gnu.org/ml/gcc-patches/2005-05/msg01249.html gcc mailling list].

+

Technically support for Lexra processors without adding emulation of these instructions would be possible but the question is how much sense it would make as some software may rely on it fairly heavily.

Following the lawsuit Lexra became a [[Instruction_Set_Architecture#MIPS32|MIPS32]] license. MIPS later acquired Lexra's [[Wikipedia:Intellectual_property|IP]]. This resulted in the end of Lexra's former products and so at this time there also seems to be little interest in actually adding Linux support.

Following the lawsuit Lexra became a [[Instruction_Set_Architecture#MIPS32|MIPS32]] license. MIPS later acquired Lexra's [[Wikipedia:Intellectual_property|IP]]. This resulted in the end of Lexra's former products and so at this time there also seems to be little interest in actually adding Linux support.

The Realtek RTL8181 is a highly integrated System-on-a-Chip with a high-performance 32-bit RISC microcontroller, two Ethernet MACs and a WLAN controller embedded onto a single chip. PCI Bridge supports one external PCI/MiniPCI device.

−

[[Analog SOC|Analog]] (ADI) are also using '''Lexra''' core for their networking processors.

+

The embedded Lexra '''LX5280''' 32-bit RISC CPU runs at up to 200MHz and features separate 8KB instruction and data caches.

Latest revision as of 07:49, 31 August 2012

Lexra did implement a 32-bit variant of the MIPS architecture. Noteworthy architectural feature was the lack of the MIPS I instructions lwl, lwr, swl and swr that optimize the handling of unaligned loads. Later the LX4580 core added hardware multithreading. Products implementing Lexra's architecture include the LX4080, LX4080P, LX4180, LX4280 and LX5280, LX8000. Today Lexra is a defunct company. Several key employees of Lexra founded the digital video core company Ultra Data Corporation, the intellectual property assets of which have since been acquired. Many other key Lexra employees, including co-founder and CEO, Charlie Cheng, now work for ASIC vendor Faraday Technology in Taiwan, Sunnyvale, CA, and Framingham, MA. Lexra co-founder and CTO Pat Hays is now vice president of engineering for MIPS Technologies, Inc. in Mountain View.

Contents

Linux support

The instructions lwl, lwr, swl and swr are covered by US patent 4,814,976. Lexra therefore choose to implement these instructions by software emulation. In the 1999 - 2002 lawsuit of MIPS Technologies, Inc. vs. Lexra, Inc. about violation of this and a second patent, Lexra and MIPS reached an agreement and the court never ruled on the matter. Which means it isn't clear if Linux can or cannot legally emulate the instructions.

Instructions emulator sourcecode from Lexra exists as Linux MIPS kernel patches and available under GPL license.

Technically support for Lexra processors without adding emulation of these instructions would be possible but the question is how much sense it would make as some software may rely on it fairly heavily.

Following the lawsuit Lexra became a MIPS32 license. MIPS later acquired Lexra's IP. This resulted in the end of Lexra's former products and so at this time there also seems to be little interest in actually adding Linux support.

Realtek RTL8181

The Realtek RTL8181 is a highly integrated System-on-a-Chip with a high-performance 32-bit RISC microcontroller, two Ethernet MACs and a WLAN controller embedded onto a single chip. PCI Bridge supports one external PCI/MiniPCI device.

The embedded Lexra LX5280 32-bit RISC CPU runs at up to 200MHz and features separate 8KB instruction and data caches.